550sx92

Hi, i have just bought a kawasaki 550sx 1992. i have never owned a jet ski and i fancied 1 for abit of a winter project.
I have a few questions which i need answering if anyone can please help me with??
I have recently removed the impeller and its housing with the fixed blades so i could inspect it for damage. once i took it off i removed the cone off the back to find oil. unfortunately i spilt the oil all over and i was wonderig what to do next? do i put new oil back in?? which oil?? or do i need to replcae some parts?

Next question: i have a flushing point tapped in to the pipe coming out from the head which goes to the exhaust. can i block the flushing point off until i need it. i am nervous that i will get water into the engine through the hose connection??? i don't understand all this flushing lark? i have always had bikes and cars and i just don't feel that water and combustion chambers mix??!!

Next question: i want a manual for my ski if anyone knows where i can get 1 from?

Next question: is there an engine cut out which you can buy for the ski as i am worried when i come to ride it, i will fall off and it wouldn't take much to lose the ski as i will be riding it in the sea?

That is all for now, any help will be very much appreciated.
Thanks
Martin